1. Field of the Invention
This invention concerns a multilayer printed wiring board having build-up portions, in which wiring patterns, laminated in plural layers via insulating layers, are electrically connected to each other by means of via holes in the insulating layers.
2. Description of the Prior Art
Various structures have been proposed for multilayer printed wiring boards having build-up portions. In the build-up portions of the proposed multilayer printed boards, wiring patterns, laminated in plural layers via insulating layers, are electrically connected to each other by means of via holes in the insulating layers. In this type of multilayer printed wiring board, the potential of the power supply line may drop instantaneously due to switching noise when a mounted semiconductor element is switched on and off at a high speed. In order to restrain such instantaneous potential drops, decoupling by connection of a capacitor portion between the power supply line and the ground line has been proposed. As a capacitor portion for this purpose, JP-A 2001-68858 proposes the provision of a layered capacitor portion inside a multilayer printed wiring board.